From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [Bug #11308] tbench regression on each kernel release from 2.6.22 -> 2.6.28 Date: Mon, 17 Nov 2008 20:43:03 +0100 Message-ID: <4921C947.9070609@cosmosbay.com> References: <20081117182320.GA26844@elte.hu> <20081117184951.GA5585@elte.hu> <20081117.113936.81699150.davem@davemloft.net> Mime-Version: 1.0 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20081117.113936.81699150.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org> Sender: kernel-testers-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="iso-8859-1"; format="flowed" To: David Miller Cc: mingo-X9Un+BFzKDI@public.gmane.org, torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, rjw-KKrjLPT3xs0@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kernel-testers-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cl-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, efault-Mmb7MZpHnFY@public.gmane.org, a.p.zijlstra-/NLkJaSkS4VmR6Xm/wNWPw@public.gmane.org, shemminger-ZtmgI6mnKB3QT0dZR+AlfA@public.gmane.org David Miller a =E9crit : > From: Ingo Molnar > Date: Mon, 17 Nov 2008 19:49:51 +0100 >=20 >> * Ingo Molnar wrote: >> >> 4> The place for the sock_rfree() hit looks a bit weird, and i'll=20 >>> investigate it now a bit more to place the real overhead point=20 >>> properly. (i already mapped the test-bit overhead: that comes from=20 >>> napi_disable_pending()) >> ok, here's a new set of profiles. (again for tbench 64-thread on a=20 >> 16-way box, with v2.6.28-rc5-19-ge14c8bf and with the kernel config = i=20 >> posted before.) >=20 > Again, do a non-NMI profile and the top (at least for me) > looks like this: >=20 > samples % app name symbol name > 473 6.3928 vmlinux finish_task_switch > 349 4.7169 vmlinux tcp_v4_rcv > 327 4.4195 vmlinux U3copy_from_user > 322 4.3519 vmlinux tl0_linux32 > 178 2.4057 vmlinux tcp_ack > 170 2.2976 vmlinux tcp_sendmsg > 167 2.2571 vmlinux U3copy_to_user >=20 > That tcp_v4_rcv() hit is %98 on the wake_up() call it does. >=20 >=20 Another profile from my tree (net-next-2.6 + some patches), on my machi= ne CPU: Core 2, speed 3000.22 MHz (estimated) Counted CPU_CLK_UNHALTED events (Clock cycles when not halted) with a u= nit mask of 0x00 (Unhalted core cycles) count 100000 samples % symbol name 223265 9.2711 __copy_user_zeroing_intel 87525 3.6345 __copy_user_intel 73203 3.0398 tcp_sendmsg 53229 2.2103 netif_rx 53041 2.2025 tcp_recvmsg 47241 1.9617 sysenter_past_esp 42888 1.7809 __copy_from_user_ll 40858 1.6966 tcp_transmit_skb 39390 1.6357 __switch_to 37363 1.5515 dst_release 36823 1.5291 __sk_dst_check_get 36050 1.4970 tcp_v4_rcv 35829 1.4878 __do_softirq 32333 1.3426 tcp_rcv_established 30451 1.2645 tcp_clean_rtx_queue 29758 1.2357 ip_queue_xmit 28497 1.1833 __copy_to_user_ll 28119 1.1676 release_sock 25218 1.0472 lock_sock_nested 23701 0.9842 __inet_lookup_established 23463 0.9743 tcp_ack 22989 0.9546 netif_receive_skb 21880 0.9086 sched_clock_cpu 20730 0.8608 tcp_write_xmit 20372 0.8460 ip_rcv 20336 0.8445 local_bh_enable 19153 0.7953 __update_sched_clock 18603 0.7725 skb_release_data 17020 0.7068 local_bh_enable_ip 16932 0.7031 process_backlog 16299 0.6768 ip_finish_output 16279 0.6760 dev_queue_xmit 15858 0.6585 sock_recvmsg 15641 0.6495 native_read_tsc 15454 0.6417 sock_wfree 15366 0.6381 update_curr 14585 0.6056 sys_socketcall 14564 0.6048 __alloc_skb 14519 0.6029 __tcp_select_window 14417 0.5987 tcp_current_mss 14391 0.5976 nf_iterate 14221 0.5905 page_address 14122 0.5864 local_bh_disable